Hypoglycemia in Dogs

Published Aug. 29, 2022
An English pointer dog looking pensive whilst resting on a sofa.

In This Article


What Is Hypoglycemia in Dogs?

Hypoglycemia or “low blood sugar” refers to a low level of circulating glucose in the bloodstream. Glucose is a small sugar molecule that comes from dog food and is utilized by their cells for energy. When the amount of sugar in the bloodstream becomes too low, the body starts to show symptoms of not having enough energy to operate. The brain especially needs a steady supply of glucose to function.

Low levels of glucose can be extremely dangerous to a dog, and this condition needs to be treated quickly. If you suspect hypoglycemia, bring your pet to a veterinarian immediately.

Health Tools

Not sure whether to see a vet?

Answer a few questions about your pet's symptom, and our vet-created Symptom Checker will give you the most likely causes and next steps.

Symptoms of Hypoglycemia in Dogs

The symptoms of hypoglycemia result from insufficient energy reaching organs of the body. These symptoms can come on suddenly or gradually depending on the cause and can also wax and wane.

If you see any of the following symptoms, please contact your veterinarian immediately:

  • Lack of appetite (anorexia)

  • Lack of energy/lethargy

  • Vomiting

  • Disorientation/weakness/ “star-gazing”

  • Tremors/seizures

  • Fainting, loss of consciousness, coma

Causes of Hypoglycemia in Dogs

There are four main categories of issues that can contribute to a dog’s blood sugar dropping lower than normal. Diseases can fall into one or more of these categories:

  • Poor dietary intake of glucose or glucose-making molecules

    • Puppy or toy breed hypoglycemia

    • Malnutrition

    • Hunting dog hypoglycemia

  • Increased glucose demand

    • Insulin overdose in diabetics

    • Xylitol toxicity

    • Insulinoma

    • Cancer

  • Insufficient utilization of or the inability to make body stores of energy molecules

  • Endocrine-system abnormalities causing hormonal imbalances

How Veterinarians Diagnose Hypoglycemia in Dogs

After examining your pet and obtaining a medical history, your veterinarian will initiate testing. These tests may include:

  • Blood glucose test—a simple bedside test that looks at blood sugar levels only.

  • Chemistry/complete blood count—a more in-depth blood test that checks red and white blood cell levels, glucose level, electrolytes, and organ function. This may be done in the hospital but may also need to be sent out to a laboratory.

Additional testing might be needed, based on initial results and your pet’s clinical signs and medication history:

  • Bloodwork

    • Bile acids—to look for liver damage

    • Hormone-level testing— may include resting cortisol levels or an ACTH stim test to look for Addison’s disease

    • Insulin/glucose ratio test—checks for circulating insulin and glucose levels to look for a potential cancer in the pancreas called an insulinoma

  • Imaging— may include radiographs/x-rays or abdominal ultrasound to check for certain types of cancer, liver disease, adrenal gland disease, or other possible causes.

Treatment of Hypoglycemia in Dogs

Treatment will depend on the severity of the situation. For pets with minimal symptoms, oral liquid glucose may be sufficient. For moderate to severe symptoms, your pet will likely be admitted to the hospital for care, which will, at a minimum, consist of intravenous (IV) fluid therapy that contains a sugar called dextrose to help bring your pet’s blood sugar up, even if it’s not eating. Additional treatments may be needed based on the initial cause of your pet’s hypoglycemia.

Recovery and Management of Hypoglycemia in Dogs

In a pet patient that had mild uncomplicated hypoglycemia, recovery is generally swift, and feeding the dog frequent small meals high in fats, protein, and complex carbohydrates will most likely be recommended. This is especially true for toy breeds and puppies recovering from hypoglycemia. Monitoring these patients to ensure they are eating is important to recovery.

Pets with moderate-to-severe or complex hypoglycemia may be hospitalized, and recovery is guarded. Treatment of the underlying cause of hypoglycemia is often necessary. For diabetic dogs, your veterinarian may recommend that you do not administer insulin, or the specialist may adjust the insulin dosage for a period after your pet is home.

Prevention of Hypoglycemia in Dogs

Prevention of hypoglycemia is highly dependent on the cause. For diabetic dogs, routine glucose monitoring after insulin administration is necessary. This may be done at home or in your vet’s office. With puppies and toy breeds, it is important to ensure that these pets are eating a high-quality diet in small, frequent meals to keep their glucose levels regulated. Patients that have underlying disease processes should be monitored frequently at their vet’s office.

Hypoglycemia in Dogs FAQs

What are four signs of hypoglycemia in dogs?

The four most common symptoms of hypoglycemia are:

  1. Weakness/lethargy

  2. Vomiting

  3. Seizures

  4. Fainting

How long does hypoglycemia last in a dog?

Hypoglycemia will last until adequate amounts of glucose are provided to the organs lacking this energy source. The lower a pet’s blood sugar has become and the longer the levels have been low, the longer it will take to recover. Pets with underlying issues that contributed to the low blood sugar level will also take longer to recover.

What happens if a dog’s blood sugar is too low?

When a dog’s blood sugar levels are too low, the body lacks the energy to perform normal functions. Symptoms can occur rapidly or gradually, depending on the cause, and may include weakness, vomiting, seizures, or fainting.


  1. Idowu O, Heading K. Hypoglycemia in dogs: Causes, management, and diagnosis. Can Vet J. 2018;59(6):642-649.

Featured Image: iStock.com/Mypurgatoryyears


Stephanie Howe, DVM


Stephanie Howe, DVM


Dr. Stephanie Howe graduated from the University of Florida College of Veterinary Medicine in 2011, after receiving a Bachelor of Science...

Help us make PetMD better

Was this article helpful?

Get Instant Vet Help Via Chat or Video. Connect with a Vet. Chewy Health